An increasing number of children survive life threatening emergencies, highly complex surgery, and acute respiratory failure and subsequently require a tracheostomy for months or sometimes years. Many of these children breathe through their tracheostomy tubes spontaneously and unassisted for hours each day when not attached to a ventilator. The major hazard for such children at home or in special care/sub-acute facilities are life threatening incidents due to occlusion and/or extubation, which may result in rapid hypoxia with devastating brain damage or death. Active, ambulatory children with tracheostomy tubes are at greatest risk since they are often not attached to any monitors and their only protection in the event of accidental decannulation is visual observation by a caregiver. The goal of the proposed project is the development of an innovative, piezoelectric-based flow system to continuously monitor pulmonary airflow in infants or children who require a tracheostomy tube and who are not connected to a ventilator. The system consists of a piezoelectric sensor that is sensitive to extremely small changes in airflow amplitude and direction. Changes in airflow are transmitted to the piezoelectric sensor via a thin lever attached to the piezoelectric crystal and positioned in the tracheostomy air stream. The motion of the lever stresses the crystal and generates an electrical signal that can be monitored. The sensor will be integrated with signal conditioning and short-range telemetry module that transmits the airflow signal to a remote receiver. An alarm will be triggered in the event of tube occlusion or accidental extubation. A prototype of the sensor and signal conditioning was constructed during Phase I of the project. Extensive bench testing demonstrated the feasibility of the concept for flow measurement and its potential for alerting the caregiver to cessation of breathing. The results of the tests also suggested the potential of the concept as a platform technology for other clinical applications. The first goal of Phase II is to increase the sensitivity of the sensor, optimize the system, integrate the sensor, signal conditioner and a telemetry unit and construct the receiver and alarm components. The second goal is to test the system clinically. The ultimate objective is to develop and prepare for commercialization a small, reliable and inexpensive system that enhances safety and mobility of the patient and is capable of monitoring multiple subjects simultaneously. [unreadable] [unreadable]